Electrochemically integrated 2D borophene–graphene architectures for energy and antimicrobial applications

Multifunctional two-dimensional architectures with integrated electrochemical and bioactive properties are highly desirable for sustainable energy and environmental technologies. Here, a non-toxic electrochemical exfoliation route is demonstrated for synthesizing borophene-graphene hybrid sheets, addressing the long-standing challenge of poor electrical conductivity in boron-based systems. Ultrasonication of graphite foils enables the effective incorporation of boron through defects, followed by controlled electrochemical exfoliation in an acidic medium, to yield stable 2D borophene-graphene hybrids. Compared to exfoliated graphene, the hybrids exhibit markedly improved electrochemical performance, achieving a specific capacitance of 254 F g^-1 and enhanced charge-transfer kinetics. In hydrogen evolution electrocatalysis, the hybrids reduce the overpotential at -100 mA cm^-2 by ∼475 mV relative to graphene and exhibit a Tafel slope of 92 mV dec^-1, which is superior to that of HER catalysts that are free of noble metals. Beyond energy applications, the hybrids demonstrate pronounced antimicrobial efficacy, achieving a reduction of more than 91% in mixed microbial cultures within 4 hours. This work establishes borophene-graphene hybrids as a scalable 2D platform that bridges high-performance energy storage, durable hydrogen evolution, and antimicrobial engineering.